Modeling Insolation, Multi-Spectral Imagery and LiDAR Point-Cloud Metrics to Predict Plant Diversity in a Temperate Montane Forest

Paul Christian Dunn,Leonhard Blesius

doi:10.3390/geographies1020006

Abstract

Incident solar radiation (insolation) passing through the forest canopy to the ground surface is either absorbed or scattered. This phenomenon, known as radiation attenuation, is measured using the extinction coefficient (K). The amount of radiation reaching the ground surface of a given site is effectively controlled by the canopy’s surface and structure, determining its suitability for plant species. Menhinick’s and Simpson’s biodiversity indexes were selected as spatially explicit response variables for the regression equation using canopy structure metrics as predictors. Independent variables include modeled area solar radiation, LiDAR-derived canopy height, effective leaf area index data derived from multi-spectral imagery and canopy strata metrics derived from LiDAR point-cloud data. The results support the hypothesis that (1) canopy surface and strata variability may be associated with understory species diversity due to radiation attenuation and the resultant habitat partitioning and that, (2) such a model can predict both this relationship and biodiversity clustering. The study data yielded significant correlations between predictor and response variables and were used to produce a multiple–linear model comprising canopy relief, the texture of heights, and vegetation density to predict understory plant diversity. When analyzed for spatial autocorrelation, the predicted biodiversity data exhibited non-random spatial continuity.

Highlights

Area solar radiation derived from the digital surface model (DSM) and the point-cloud and imagery met
Significant relationships were evident between the canopy structure and biodiversity data as well
While the available data did not indicate a relationship of significant magnitude between modeled radiant flux and observed biodiversity, there was a significant relationship between canopy height (CH) and diversity, depending on how diversity was measured

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Spatial ecologists and biogeographers study the variation of plant species across spatial scales and latitudinal gradients. This spatial variability and its link to ecological and biogeochemical processes are considered by some researchers to be fundamental to biological inquiry [1] and understanding biological diversity a central research problem in modern biology. The spatial analysis of biota often focuses on either species distribution or species biodiversity within communities, landscapes and ecosystems, or genetic systems associated with spatial scales such as species populations. The discipline of phytogeography provides one such example, combining geography and botany to investigate the spatial distributions of plant species and their communities.

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